Autism Spectrum Disorder (ASD) is a neurodevelopmental condition that affects social interaction, communication, and behavior. It’s a complex disorder that is still misunderstood in many ways.
In the past, autism was organized into five categories, each with its own markers and challenges. Today, however, the Diagnostic and Statistical Manual of Mental Disorders (DSM-5) acknowledges that autism is a single condition with a spectrum of characteristics and degrees of severity.
While we no longer use the five subtypes, they were created based on clinical observations by renowned doctors, Leo Kanner and Hans Asperger. Knowledge of these five subtypes still provides valuable insights into the autism spectrum and the diversity of its traits today.
The 5 Types of Autism Spectrum Disorders
Let’s take a look at the five subtypes of autism that were first used to organize the complex spectrum of this disorder.
Rett Syndrome
Rett Syndrome is a rare genetic neurological disorder that primarily affects females and the nervous system. It was first described in 1966 by Andreas Rett in his paper “On an unusual brain atrophy syndrome in Hyperammonemia in Childhood”.
Rett Syndrome differs from other types of autism, as Rett is caused by the mutation of the MECP2 gene.
However, not everyone with this mutation will show Rett symptoms and there are also cases of Rett Syndrome being diagnosed without the mutated MECP2 gene.
With Rett Syndrome, children experience a period of normal development after birth. It’s usually after the 6 to 18-month mark that researchers notice the condition.
Symptoms include a loss of hand skills, delayed growth, breathing difficulties, and severe cognitive impairment.
While Rett was part of the autism subtypes, it’s been moved from the autism spectrum into a classification of its own. Today, it’s known as a genetic disorder with symptoms that look a lot like autism but aren’t.
Autistic Disorder or Kanner’s Syndrome
Kanner’s Syndrome, also known as Classic Autism or Autistic Disorder, is the type that most people will think of when we picture autism. It was first classified by Dr. Leo Kanner, in his groundbreaking paper published in 1943 called “Autistic Disturbances of Affective Contact, The Nervous Child”.
His work was the foundation for early autism research and is still relevant today. With his research, it was possible to establish the core characteristics of significant challenges in social interaction and restricted repetitive behaviors that are common in autism.
Some common signs of Kanner’s Syndrome can include but are not limited to intellectual disability, difficulty understanding social cues, echolalia, and little interest in engaging with others or the surrounding environment. There may also be hyperfixation of specific interests and sensitivity to stimuli, such as sound, or sensory cues.
Asperger’s Syndrome
Asperger’s Syndrome was adopted as a condition following Asperger’s 1944 paper “Die Autistischen Psychopathen”. It was named after the Austrian pediatrician Hans Asperger, whose research was enough to create a distinctive category for the condition.
Asperger’s Syndrome is marked by individuals having above-average intelligence. They also tend to excel in specific academic or artistic areas. Nevertheless, they tend to struggle with social interactions, understanding nonverbal communication, and forming relationships.
People with Asperger’s Syndrome don’t usually have the same language delays as the other types of autism on this list. However, their speech is almost always more formal than normal.
Asperger’s is no longer an official diagnosis, as autism falls on a spectrum, and is considered controversial due to Hans Asperger’s history. However, many who deal with this specific set of symptoms still use the term to describe their condition.
Childhood Disintegrative Disorder (CDD)
Childhood Disintegrative Disorder (CDD), also known as Heller’s Syndrome, is a rare and severe form of autism. It was first described by Austrian educator Theodore Heller in 1908, in their paper on “Childhood disintegrative disorder”. According to Heller, CDD is marked by a significant regression after at least two years of normal development.
Children with CDD lose their language skills, social skills, motor abilities, and bladder or bowel control during this regression. The regression, which occurs mostly in children ages 3 to 10, can be sudden and dramatic.
Childhood Disintegrative Disorder was absorbed into the autism disorder spectrum in 2013.
Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS)
Pervasive Developmental Disorder – Not Otherwise Specified (PDD-NOS) described people who showed certain autistic characteristics defined by the American Psychiatric Association. This included difficulties with social interaction, communication, and behavior.
However, people with PDD-NOS did not completely fit the criteria for the above subtypes, so they were listed under this “catch-all” term. It was mostly used to describe children who showed signs of autism, but who didn’t have severe enough symptoms to be diagnosed with Kanner’s or Asperger’s Syndrome.
It was this disorder that first acknowledged the diverse and flexible nature of autism. It showed that autism did not appear uniformly across all individuals, and lay more on a spectrum than a chart.
Current Categorizations of Autism
It was in 2013 that the DSM-5 redefined autism and its criteria. The above subtypes were merged into the diagnoses we use today, Autism Spectrum Disorder (ASD), and accepted the diverse nature of this condition.
This, of course, was only done after an extensive body of research could prove that autism is a spectrum with a wide range of symptoms and severity levels rather than a collection of separate disorders.
Today, the DSM-5 focuses on ASD diagnoses based on two key characteristics: 1.) communication and interaction difficulties, and 2.) restricted, repetitive behavior, interests, or activities.
The ASD diagnosis more readily reflects the reality of this disorder. Specifically, the different symptoms of the disorder and how the severity of it affects individuals. This has allowed for a much more individualized approach to diagnosis and treatment.
The Different Levels of Autism
Different types of disabilities and their impact on daily life differ across the board. By defining the support levels of people with ASD, we can provide tailored support that improves their quality of life.
The DSM-5 outlines three levels of severity:
- Level 1: People who require some support but who are otherwise independent.
- Level 2: These are the individuals who require substantial hands-on support, especially when completing tasks and during social interactions.
- Level 3: Individuals who require extensive support for daily living and may need assistance with basic tasks.
Conclusion
Today, it’s accepted that autism lies on a spectrum and doesn’t have specific, individual conditions. However, these first distinct subtypes still taught us a lot about this disorder and are still relevant in research today.
These earlier classifications were integral in helping the medical community understand the complexity of this condition. By accepting autism on a spectrum, diagnostics criteria now focus on autism severity to determine the best help for those with the condition.
If you or someone you know requires help with ASD or another condition, contact 365 Health Service’s IDS department at (610) 228-0057 for dedicated support and home care.
